The present invention relates to an auto-feed control mechanism for computerized numerically-controlled (CNC) spring forming machines, in which a tool handle is mounted in front of the spring forming machine near a steel wire feeding end thereof and can be driven by motors to move forward or backward, and to rotate and/or incline and be positioned at any desired angle, so that a tool connected to the tool handle can be more actively manipulated to bend a steel wire to form various kinds of irregularly-shaped springs at reduced cost and in higher efficiency.
In a conventional manner of forming a spring, a spring forming machine having an automatic wire feeding mechanism is used together with a multi-jaw tool feeding mechanism attached to the front of the spring forming machine, so that the tool feeding mechanism shall moves the tool to form the fed steel wire at a point near the wire-feeding end of the spring forming machine and thereby automatically bends or deforms the steel wire to form a spring with a desired shape.
In the above mentioned multi-jaw tool feeding mechanism, the linear feeding of tools is not active enough for the present spring forming process, because the spring itself usually has different winding and bending angles while the tools are fed at an equal circumferential angle within a plane normal to the feeding direction of the wire. When the wire is continuously fed, the tool feeding mechanism on each jaw timely extends one by one under the control of a CNC program controlled system, such that two tools separately support and press the wire and respectively function as a fulcrum and an upper application point, forcing the spring steel wire to automatically wind to form the desired shape.
The disadvantages existed in the conventional multi-jaw tool feeding mechanism further include:
1. Each tool handle of the multi-jaw tool feeding mechanism is individually extended to wind and bend the steel wire during the forming of spring. Due to this individual movement of each tool handle, the tool feeding mechanism has a very complicated structure with numerous parts and components and, therefore, accounts for a very high manufacture cost of the conventional spring forming machine. PA1 2. Since each of the tools mounted on the movable jaws of the spring forming machine is linearly fed at an equal circumferential angle, differently shaped tools are required to form springs with special shapes. Such specially shaped tools are usually manually ground and formed by skilled workers which is extremely time and labor consuming. PA1 3. Since each of the tool handles is mounted on the front panel of the spring forming machine, the tools are fed in a direction normal to the direction in which the wire is fed. Therefore, dead angles exist when the wire is bent, and springs with more complicate bending angles are be very difficult to form. PA1 4. Since the tools can only be fed in the same plane, two tools are required to separately function as a fulcrum and an application point to wind a steel wire. After the wire is bent and formed in this way, cracks are frequently found on the wire surface at fulcrums thereof due to focused stress.
It is therefore the present inventor has developed an auto-feed control mechanism for the CNC spring-forming machine that eliminates the above mentioned disadvantages.